Telephone ringing device.



H N. PARIS.

TELEPHONE RINGING DEVICE.

APPLICATION FILED PEB. 1a, 1909.

1,007,684, Patented N0v.7,1911.

Wam

UNITED STATES PATENT OFFICE.

HARRY N. FARIS, 0F KANSAS CITY, KANSAS.

TELEPHONE RINGING- DEVICE.

To all whom t may concern.'

Be it known that I, HARRY N. FARIs, a citizen of the United States of America, and a resident of Kansas City, county of Wyandotte, and State of Kansas, have invented a new and useful Im rovement in Telephone Ringing Devices, of) which the following is a specification.

My invention pertains to methods and apparatus for generating ringing currents in a telephone central office for the purpose of ringing telephone bells.

My object is to provide a system of current generating devices which will operate effectively in delivering ringing currents when called upon to do so, and will maintain a condition of readiness for operation during those periods when not called upon for delivery of ringing current, the condi? tion of readiness for action being maintained at a minimum of wasted energy.

My invention is designed primarily for use in connection with current generating systems in which the prime sourcevof energy is a galvanic battery associated with an inductive transformer, and the method which I use to conserve the energy of the battery when the system is not called upon to deliver ringing current is to open the battery circuit supplying the primary winding of the transformer during the periods when current is not required, and to close the circuit automatically when the ringing current is required. The means which I use to accomplish this result is embodied in a portion of the current generating equipment, and as a result of such embodiment the current generating equipment acts automatically and as a complete unit delivering a current suitable for ringing whenever a circuit is provided through which said current may be delivered and acting to maintain itself in a state of readiness to deliver such current at all times, but with a minimum consumption of energy when a circuit for the delivery of current does not exist.

In the drawings accompanying, Figure l shows a preferred form and Fig. 2 a modified form of the circuit of my invention. Fig. 3 shows essential portions of the circuit of a telephone switchboard.

The divers units of apparatus involved are not necessarily especially designed for use in my invention and for that reason specic mechanical details are not given, all

Specification of Letters Patent.

Application led February 13, 1909. Serial No. 477,762.

Patented Nov. 7, 191.1.

parts being represented by recognized symbols.

Referring first to Fig. l, J and M are conductors leading to the ringing bus bars of the telephone switchboard. Conductor J passes through winding of relay R with shunt lamp L1 to terminal H of secondary S of the transformer. 'Ihe conductor M may pass through contact E and armature A of relay R to the terminal N of the secondary S of the transformer when the relay R is energized, and at other times it is connected through battery Bl and resistance lamp L2 to the terminal N. It will be seen that when an external circuit is provided from J to M that current from B1 will flow, energizing relay R and closing the path from M to N directly.

Battery B2 supplies energy continuously for operating the vibrator armature V by control of its back contact Y and magnet Q. Magnet Q, is shunted by the noninductive resistance F. The armature V vibrates continuously. By the vibrating armature V and its contacts W and X the potential of battery B1 passes out through keys K1 and K2 and primary windings P1 and P2 to junction point I, thence to N, thence to armature A of relay R, where the circuit is open; hence current does not flow. Upon the closure of an external path between conductors J and M, current flows through M, B1, L2, N, S, H, R, J and external path energizing R and closing A to E. The closure of A to E removes the potential of battery B1 from N, S, H, R and external path (leaving the lamp L2 as a direct resistance across battery B1) and therefore depriving R of the current -which energized it. By the closure of A to E, however, current is permitted to flow through B1, V, W, K1, P1, I, N, A, E, (and alternatively through X K2 P2), thus energizing t-he transformer, and creating an alternating potential in thesecondary S which then furnishes a ringing current through the circuit, M, E, A, N, S, H, R, J, and the external path. The relay R is thus provided with alternating current immediately upon the cessation of the direct current causing its initial energization and the intensity of this current will be equal to or greater than a predetermined minimum value since the external path from J to N must be below a predetermined maximum resistance to cause the energizing of relay R primarily. The

--the potential generating windin relay R is one adapted to retain its-armature in attracted position when energized by alternating or pulsatory ringing current.

VRelays of this type are obtainable comidleness no current from battery B1 is usedv and that a normal current from battery B2 is used. The potential of'battery B1 is upon the conductors J and M which are open at the telephone switchboard. Upon the closure of conductors J and M through the external path the potential of battery B1 is removed from those conductors and the path from those conductors through the generating device is cleared of all apparatus other than l S and controlling. relay R. The conditlons thus are suitable for generating a maximum current for ringing purposes, being those encountered in a continuously operating transformer with the addition of the controlling relay R. 0

In ringing upon metallic circuit telephone lines, the external path from J to N will be found through the lines conductors and the ringer bridge of the telephone sub-station. This will give a maximum resistance of probably 1500 ohms. In ringing upon grounded telephone lines the rlnglng bridge at the substation will include a ground connection and this ground connection may be 'defective from any one of several causes: The connection ma be of high resistance by reason of defective contact between conductors; t-he connection may be to earth by means of a ground rod driven in dry earth, which is likely to be of abnormally high resistance for ringing purposes; the earth connection may be polarized; the earth current from street railway or other sources may oppose the potential of battery B1 and eiect a reduction of current. To obviate interference in my automatic ringing device through any of these causes, by rendering it independent of the ground connection, or indeed, of any connection at the telephone sub-station, I provide a circuit wholly within the central oiiice, which circuit may be completed by the operation of connecting the ringing bus bars of the switchboard to the conductors of the line to be rung upon. -In the circuit of lines of some well known types of telephone switchboards the jack body J1 is connected to earth through the winding of cut-o relay R1. In such a switchboard when the plug P3 is inserted in the jack and ringing key K3 is operated the conductor M is connected through conductor T plug P3 jack J1 and relay R1 to earth. Through conductor J a path is taken Leonesa through impedance O t6 earth at G. Thus I establish a local path from M through K3, T, P8, J1, R1, earth, G, O to J, Within the central oflice of the telephone exchange, which local circuit contains only the usual elements of the telephone equipment, and the elements contained in my ringing current generating device. This circuit .is adapted to be closed by the act of ringing upon any telephone line whether metallic or grounded. By this circuit the relay R is provided with a circuit of maximum resistance which is entirely independent of the resistance, or of; the operativeness or inoperativeness of the line attempted to be rung upon, and my improved ringing device will deliver the desired ringing potential to that line. At the same time the local circuit thus secured will maintain the energization of relay R by alternating current from winding S without the cooperation of the linev attempted to be rung upon.

In Fig. 2 a modiication is shown in which relay R has a back contact D adapted to remove potential of battery B1 from the circuit ot' conductors J and M. It is obvious that relay R may be constructed in any of a large number of permutations with respect to its `armature contacts. Keys K1 and K2 are introduced for the purpose of ringing biased polarized telephone bells selectively. It is knowrl that the potential in the secondary winding caused by the breaking of the primary circuit is much greater than the potential caused by the making of the primary circuit, and the design of the transformer having the secondary S and split primary P1 and P2 is such that the potential of .the

breaking of the primary circuit is obtained A in the secondary winding Iirst in one direction and then in the opposite direction. By this means a luniform alternating current is secured, the currents in a positive direction being equal to the currents in the negative direction and alternating with them. By opening key K1 preparatory to ringing upon a telephone line, primary winding P1 will not be permitted to carry current, and currents generated in secondary S will be solel those resulting from current through pr1- mary P1. The result will be a distorted alternating current in which the potential of the waves of one polarity will be much in excess of the potential of the waves of the other polarity. Such current is suited for ringing biased polarized bells. The polarity of biased or pulsatory current may be predetermined by operating keys K1 or K2 as desired. By including in the conductor J or conductor M a source of direct current, the objectionable phase of the distorted current thus produced may be opposed and eliminated, the desired phase being, at the same time, amplified, and the current thus bebells. It will be noted also that the periodicity of the resulting current is proper for such bells. I have shown two batteries, Bl

and B`'. The battery B1 is inactive exceptA during the operation of ringing, and the batter)v B2 is active atl all times to maintain the vibration of the armature V. It is desirable that the armature V operate continuously to secure clearly cut signals in ringing codes. There ringing codes is not required it is obvious that the energy of the battery Bl may be conserved by including in its circuit a Contact controlled by armature A of the relay R. By maintaining battery B2 separate from battery B1, battery B1 is ready to give its full current in the primary circuit of transformer, even though battery B2 may bc to some extent deteriorated by its continuous service in operating the vibrator. It may be found a convenience in many instances also to have these batteries of diHerent potentials. It is obvious that the two circuits may be operated upon the same battery where this is desirable, as is the case where a storage battery forms a part of the central oiiice equipment, and my invention is not in any way limited to a system in which two batteries are included. I have illustrated this by sho-Wing the switch Z adapted to connect together batteries Bl and B2 in Fig. l, thereby uniting them into a single battery.

It is obvious that many modifications may be made without departing from the scope of my invention.

IVhat I claim as new and desire to secure by United States patent is:

1. In a telephone ringing system, a transformer containing secondary and primary windings; a secondary circuit containing said secondary winding, and adapted to be closed through an external path; a relay also included in said secondary circuit; and a primary circuit including said primary winding, a source of current and contacts of said relay.

2. In a telephone ringing system, a transformer containing secondary and primary windings; a secondary circuit containing said secondary winding, and adapted to be closed through an external path; a relay also included in said secondary circuit; and a primary circuit including said primary winding, a source of current and normally open contacts of said relay.

3. In a telephone ringing system, a transformer containing secondary and primary windings; a secondary circuit containing said secondary winding, and adapted to be closed through an external path; a source of constant potential and a relay also included in said secondary circuit; and a primary circuit including said primary winding, a source of current and contacts of said relay.

4. In a telephone ringing system, a transformer having primary and secondary Windings; a secondary circuit including a source ot' current, a relay and said secondary winding, said relay being adapted to remove by the operation of its armature any direct current which may have been flowing in said secondary circuit, from said source of potential, prior to the operation of said relay.v

In a telephone ringing system, a transformer having a primary and a secondary winding; a secondary circuit including a source of current, a relay and said secondary winding; said relay being adapted to shunt by the operation of its armature any direct current '(from said source of potential) which may have been flowing in said secondary circuit prior to the operation of said relay.

6. In a ringing system for telephone eX- changes, a. transformer having primary Aand Secondary windings; a secondary circuit including in the order named: a relay, a secondary winding, a resistance and a battery and means for connecting a path to complete the circuit, a contact of said relay being adapted to close a shunt about said battery and said resistance.

7. In a telephone ringing system, a transformer containing secondary and primary windings; a secondary circuit containing said secondary winding and adap-ted to be closed through an external path; a primary circuit including said primary Winding, a source of current and vibrator contacts; and a relay whose winding is included in said secondary circuit and which is adapted to render said primary circuit operative.

8. In a telephone ringing system, a transformer containing secondary and primary windings; a secondary circuit containing said secondary winding and adapted to be closed through an external path; a primary circuit including said primary winding, a source of current and vibrator contacts; and means controlled by said secondary circuit and controlling said primary circuit to render said primary winding active or inactive. l

9. In a telephone ringing system, a transformer having primary and secondary windings; a secondary circuit including a source of current, a relay and said secondary Winding, said relay being adapted to remove by the operation of its armature any direct current which may have been flowing in said secondary circuit from said source of potential prior to the operation of said relay, and to render said primary Winding active.

10. In a telephone ringing system, a transformer' having a primary and a secondary winding; a secondary circuit including a source of current, a relay and said secondary winding; said relay being adapted to shunt by the operation of its armature any direct current which may have been flowing in said secondary circuit prior to the operation of said relay, and to render said primary Winding operative.

11. In a ringing system for telephone eirchange, a transformer havin primary and secondary windings; a secon ary circuit including the following elements and connected in series in the order named: a relay, a secondary winding, a resistance and a battery and means Jfor connecting a ath to complete the circuit, a contact of sai rela being adapted to close a shunt about said attery and said resistance; and a primary circuit path connected in multiple with said resistance and containing vibrator contacts and a primary winding of said transformer.

12. In a ringing system, a device constituting a source of ringing current adapted to be rendered operative by the closing of a conducting path between its terminals; a branch conductor from one terminal of said device to a commonereturn conductor; a connection in the telephone switchboard from said common-return to a line conductor of a telephone line; and a ringing key constituting means for connecting said line conductor to the remaining terminal of said source of ringing current.

13. In a telephone ringing system, a transformer containing secondary and primary windings; a secondary circuit containing said secondary winding and adapted to be closed through an external path; a relay also included in said secondary circuit; a primary circuit including said primary winding, a source of current and contacts of said relay;

noemer,

a ground branch connection upon one termi nal of said secondary circuit; and external path including a ringing key, a talking conductor and a cutoii:1 relay winding.

la. ln a telephone ringing system, a transformer containing a secondary and two primary windings; a secondary circuit containing said secondary winding and adapted to be closed through an external path; a relay also included in said secondary circuit and a primary circuit including a source of current, normally o en contacts of said relay, and a'vibrator c osing circuit through said primaries alternately; and other means for interrupting the conductor of one only of said primaries.

15. In a telephone ringing system, a transformer containing a secondary and two primary windings; a secondary circuit containing said secondary winding and adapted to be closed through an external path; a relay also included in said secondary circuit; and a primary circuit including a source of current, normally open contacts of said rela and a Vibrator closing circuit through said primaries alternately; and other means permitting the closure of but one of said primaries.

Signed by me at Kansas City, county of Jackson and State of Missouri, in the presence of two witnesses.

HARRY N. FARIS.

Witnesses:

J. P. JORDAN, WM. E. GILL. 

